Electrical heating elements have long been known in the prior art, as is well documented by the vast number of patents referred to in the attached Prior Art Statement. These heating elements have been utilized in a number of tools, such as soldering irons, curling irons and more recently hot melt glue guns. While these tools have been utilized in the field for many years, they all have one major problem in common --namely, they must be electrically connected to a conventional 110 volt power source. This makes their portability quite limited, since an extension cord is always required.
These tools share a number of other problems which also relate to the lack of portability in the devices. Known tools which utilize electrical heating elements require very high temperatures in order to operate. These high temperatures are produced using electrical resistance in coil wrapped around a heavy, solid core, the core retaining the heat for long periods of time. However, besides being heavy, the conventional heating element requires a large voltage or current for an extended period of time in order to heat the core to the desired temperature. For this reason, it was heretofore unknown and believed infeasible to utilize conventional flashlight-type batteries to supply the power to the tool.
While "cordless" operation has been recently introduced in the field for drills, screwdrivers, flashlights and small vacuums, such devices utilize a high current power source. For this reason it was not possible to operate a tool merely by plugging the tool via its "power pack" into a conventional A.C. power source. The power pack supplies only a small current to the rechargeable batteries to recharge them. The low current is unable to actually operate the tool. In the same manner, use of an adaptor or converter which plugs into the cigarette lighter of a car to access the 12 volt battery source of the car would likewise not be able to supply the needed current to operate the tool.
Another problem with conventional tools which have electrical heating elements is in the amount of time required to heat the element to the required temperature, and the amount of time required for the heated element to cool off after use. Because of the heavy weight and large mass of the cores on conventional heating elements, it can be seen that the amount of time and power required to heat the heat element core was substantial. These large mass cores were required, however, in order to maintain the extremely high temperatures of 250.degree.-400.degree. F necessary for melting solder, thermal plastic, etc. --as used in soldering irons, and hot melt glue guns.
Yet another problem with the conventional tools utilizing electrical heating elements is in the fact that it is difficult to illuminate the work area during operation of the tool. While hot glue guns and soldering irons in the prior art disclose that light bulbs have been used in an attempt to illuminate the work area, the location of the light bulb made it difficult to adequately illuminate the desired area.
Still a further problem with prior art curling irons, soldering irons and hot glue guns is in the difficulty in replacing the electrical heat elements in these tools. Not only is the heating element typically permanently attached, but is very complicated and expensive to replace.
All of these devices are also a potential electrical hazard because of the use of 110 volt household current. Use of a curling iron in a bathroom and near water is especially dangerous, but is a common problem.